Re: [CentOS] Short or long hostname ?
>> >> >> On 4/10/19 8:23 AM, Simon Matter via CentOS wrote: Hi, For the last ten years or so, I've defined the short hostname in /etc/hostname and the FQDN in /etc/hosts. Now I wanted to double-check this information, which eventually led me to this page: * https://serverfault.com/questions/331936/setting-the-hostname-fqdn-or-short-name Now I admit I'm even more confused than before. Is there some reliable piece of information on this subject for CentOS ? >>> >>> IMHO for those having proper DNS in place, the hostname should be set >>> to >>> the FQDN in whatever place it is supposed to be set. I quite feel there >>> is >>> something wrong if the only place where the FQDN is listed is the >>> /etc/hosts file. >>> >>> I'm not very happy with how the issue was handled in Linux and the >>> different distributions in the last decades. Not to mention the >>> inconsistency in the relevant man pages. >> >> Well, I am unhappy for about as long about /etc/hosts and how name >> resolution "should" happen which it doesn't, namely, if >> /etc/nsswitch.conf says >> >> hosts: files dns >> >> then ideally /etc/hosts should be used first, then nameservers. However >> (and this is true both for Linux and FreeBSD), some commands never look >> into /etc/hosts (e.g., command host), whereas some do use /etc/hosts >> (e.g., command ping). > > Well, in case of the host command it seems clear that it doesn't look up > /etc/hosts as it is a "DNS lookup utility", as the man page states, and > not a general name resolution utility. I had to learn this, guess how. It's my impression that trying to resolve a host on a Linux system (and also other *nix like systems) is best done with the getent utility: getent hosts It shows what other programs see as well. Regards, Simon ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Short or long hostname ?
On Apr 10, 2019, at 09:23, Simon Matter via CentOS wrote: > IMHO for those having proper DNS in place, the hostname should be set to > the FQDN in whatever place it is supposed to be set. I quite feel there is > something wrong if the only place where the FQDN is listed is the > /etc/hosts file. If you ever plan on using Kerberos, you want the host name to use FQDN, otherwise some krb5 stuff can break. — Jonathan Billings ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Short or long hostname ?
> > > On 4/10/19 8:23 AM, Simon Matter via CentOS wrote: >>> Hi, >>> >>> For the last ten years or so, I've defined the short hostname in >>> /etc/hostname and the FQDN in /etc/hosts. Now I wanted to double-check >>> this information, which eventually led me to this page: >>> >>>* >>> https://serverfault.com/questions/331936/setting-the-hostname-fqdn-or-short-name >>> >>> Now I admit I'm even more confused than before. >>> >>> Is there some reliable piece of information on this subject for CentOS >>> ? >> >> IMHO for those having proper DNS in place, the hostname should be set to >> the FQDN in whatever place it is supposed to be set. I quite feel there >> is >> something wrong if the only place where the FQDN is listed is the >> /etc/hosts file. >> >> I'm not very happy with how the issue was handled in Linux and the >> different distributions in the last decades. Not to mention the >> inconsistency in the relevant man pages. > > Well, I am unhappy for about as long about /etc/hosts and how name > resolution "should" happen which it doesn't, namely, if > /etc/nsswitch.conf says > > hosts: files dns > > then ideally /etc/hosts should be used first, then nameservers. However > (and this is true both for Linux and FreeBSD), some commands never look > into /etc/hosts (e.g., command host), whereas some do use /etc/hosts > (e.g., command ping). Well, in case of the host command it seems clear that it doesn't look up /etc/hosts as it is a "DNS lookup utility", as the man page states, and not a general name resolution utility. I had to learn this, guess how. But all in all it's a bit of a mess, yes. Unfortunately I'm tempted to expect that systemd-resolved will even make it worse :-) Regards, Simon > > Valeri > >> >> I found the info mentioned in the FreeBSD man pages quite helpful even >> if >> it has to be "translated" to Linux. See the excerpt of the mentioned man >> pages below. If you believe this is heresy to be posted here, please >> don't >> read it :-) >> >> Regards, >> Simon >> >> %>--- >> root@freebsd:~ # man hostname >> HOSTNAME(1) FreeBSD General Commands Manual >> HOSTNAME(1) >> >> NAME >> hostname - set or print name of current host system >> >> SYNOPSIS >> hostname [-f] [-s | -d] [name-of-host] >> >> DESCRIPTION >> The hostname utility prints the name of the current host. The >> super-user >> can set the hostname by supplying an argument; this is usually >> done in >> the initialization script /etc/rc.d/hostname, normally run at boot >> time. >> This script uses the hostname variable in /etc/rc.conf. >> ... >> >> >> root@freebsd:~ # man rc.conf >> RC.CONF(5)FreeBSD File Formats Manual >> RC.CONF(5) >> >> NAME >> rc.conf - system configuration information >> >> DESCRIPTION >> The file rc.conf contains descriptive information about the local >> host >> ... >> hostname (str) The fully qualified domain name (FQDN) of this host >> on >>the network. This should almost certainly be set to >>something meaningful, even if there is no network >> connection. >>If dhclient(8) is used to set the hostname via DHCP, this >>variable should be set to an empty string. Within a >> jail(8) >>the hostname is generally already set and this variable >> may >>absent. If this value remains unset when the system is >> done >>booting your console login will display the default >> hostname >>of "Amnesiac". >> >> ___ >> CentOS mailing list >> CentOS@centos.org >> https://lists.centos.org/mailman/listinfo/centos >> > > -- > > Valeri Galtsev > Sr System Administrator > Department of Astronomy and Astrophysics > Kavli Institute for Cosmological Physics > University of Chicago > Phone: 773-702-4247 > > ___ > CentOS mailing list > CentOS@centos.org > https://lists.centos.org/mailman/listinfo/centos > ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Short or long hostname ?
On 4/10/19 8:23 AM, Simon Matter via CentOS wrote: Hi, For the last ten years or so, I've defined the short hostname in /etc/hostname and the FQDN in /etc/hosts. Now I wanted to double-check this information, which eventually led me to this page: * https://serverfault.com/questions/331936/setting-the-hostname-fqdn-or-short-name Now I admit I'm even more confused than before. Is there some reliable piece of information on this subject for CentOS ? IMHO for those having proper DNS in place, the hostname should be set to the FQDN in whatever place it is supposed to be set. I quite feel there is something wrong if the only place where the FQDN is listed is the /etc/hosts file. I'm not very happy with how the issue was handled in Linux and the different distributions in the last decades. Not to mention the inconsistency in the relevant man pages. Well, I am unhappy for about as long about /etc/hosts and how name resolution "should" happen which it doesn't, namely, if /etc/nsswitch.conf says hosts: files dns then ideally /etc/hosts should be used first, then nameservers. However (and this is true both for Linux and FreeBSD), some commands never look into /etc/hosts (e.g., command host), whereas some do use /etc/hosts (e.g., command ping). Valeri I found the info mentioned in the FreeBSD man pages quite helpful even if it has to be "translated" to Linux. See the excerpt of the mentioned man pages below. If you believe this is heresy to be posted here, please don't read it :-) Regards, Simon %>--- root@freebsd:~ # man hostname HOSTNAME(1) FreeBSD General Commands Manual HOSTNAME(1) NAME hostname - set or print name of current host system SYNOPSIS hostname [-f] [-s | -d] [name-of-host] DESCRIPTION The hostname utility prints the name of the current host. The super-user can set the hostname by supplying an argument; this is usually done in the initialization script /etc/rc.d/hostname, normally run at boot time. This script uses the hostname variable in /etc/rc.conf. ... root@freebsd:~ # man rc.conf RC.CONF(5)FreeBSD File Formats Manual RC.CONF(5) NAME rc.conf - system configuration information DESCRIPTION The file rc.conf contains descriptive information about the local host ... hostname (str) The fully qualified domain name (FQDN) of this host on the network. This should almost certainly be set to something meaningful, even if there is no network connection. If dhclient(8) is used to set the hostname via DHCP, this variable should be set to an empty string. Within a jail(8) the hostname is generally already set and this variable may absent. If this value remains unset when the system is done booting your console login will display the default hostname of "Amnesiac". ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos -- Valeri Galtsev Sr System Administrator Department of Astronomy and Astrophysics Kavli Institute for Cosmological Physics University of Chicago Phone: 773-702-4247 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Short or long hostname ?
> Hi, > > For the last ten years or so, I've defined the short hostname in > /etc/hostname and the FQDN in /etc/hosts. Now I wanted to double-check > this information, which eventually led me to this page: > > * > https://serverfault.com/questions/331936/setting-the-hostname-fqdn-or-short-name > > Now I admit I'm even more confused than before. > > Is there some reliable piece of information on this subject for CentOS ? IMHO for those having proper DNS in place, the hostname should be set to the FQDN in whatever place it is supposed to be set. I quite feel there is something wrong if the only place where the FQDN is listed is the /etc/hosts file. I'm not very happy with how the issue was handled in Linux and the different distributions in the last decades. Not to mention the inconsistency in the relevant man pages. I found the info mentioned in the FreeBSD man pages quite helpful even if it has to be "translated" to Linux. See the excerpt of the mentioned man pages below. If you believe this is heresy to be posted here, please don't read it :-) Regards, Simon %>--- root@freebsd:~ # man hostname HOSTNAME(1) FreeBSD General Commands Manual HOSTNAME(1) NAME hostname - set or print name of current host system SYNOPSIS hostname [-f] [-s | -d] [name-of-host] DESCRIPTION The hostname utility prints the name of the current host. The super-user can set the hostname by supplying an argument; this is usually done in the initialization script /etc/rc.d/hostname, normally run at boot time. This script uses the hostname variable in /etc/rc.conf. ... root@freebsd:~ # man rc.conf RC.CONF(5)FreeBSD File Formats Manual RC.CONF(5) NAME rc.conf - system configuration information DESCRIPTION The file rc.conf contains descriptive information about the local host ... hostname (str) The fully qualified domain name (FQDN) of this host on the network. This should almost certainly be set to something meaningful, even if there is no network connection. If dhclient(8) is used to set the hostname via DHCP, this variable should be set to an empty string. Within a jail(8) the hostname is generally already set and this variable may absent. If this value remains unset when the system is done booting your console login will display the default hostname of "Amnesiac". ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Re: [CentOS] Short or long hostname ?
How I do it ( and always done it): hostnamectl set-hostname foobar.localdomain echo 127.0.0.1 foobar.localdomain foobar >> /etc/hosts echo ::1 foobar.localdomain foobar >> /etc/hosts -- Sent from the Delta quadrant using Borg technology! Nux! www.nux.ro - Original Message - > From: "Nicolas Kovacs" > To: "CentOS mailing list" > Sent: Wednesday, 10 April, 2019 08:21:11 > Subject: [CentOS] Short or long hostname ? > Hi, > > For the last ten years or so, I've defined the short hostname in > /etc/hostname and the FQDN in /etc/hosts. Now I wanted to double-check > this information, which eventually led me to this page: > > * > https://serverfault.com/questions/331936/setting-the-hostname-fqdn-or-short-name > > Now I admit I'm even more confused than before. > > Is there some reliable piece of information on this subject for CentOS ? > > Cheers, > > Niki > -- > Microlinux - Solutions informatiques durables > 7, place de l'église - 30730 Montpezat > Site : https://www.microlinux.fr > Mail : i...@microlinux.fr > Tél. : 04 66 63 10 32 > Mob. : 06 51 80 12 12 > ___ > CentOS mailing list > CentOS@centos.org > https://lists.centos.org/mailman/listinfo/centos ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
[CentOS] Short or long hostname ?
Hi, For the last ten years or so, I've defined the short hostname in /etc/hostname and the FQDN in /etc/hosts. Now I wanted to double-check this information, which eventually led me to this page: * https://serverfault.com/questions/331936/setting-the-hostname-fqdn-or-short-name Now I admit I'm even more confused than before. Is there some reliable piece of information on this subject for CentOS ? Cheers, Niki -- Microlinux - Solutions informatiques durables 7, place de l'église - 30730 Montpezat Site : https://www.microlinux.fr Mail : i...@microlinux.fr Tél. : 04 66 63 10 32 Mob. : 06 51 80 12 12 ___ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
